This invention relates generally to terrarium structures, and more particularly to a hermetically-sealed collapsible terrarium assembly which includes a replaceable dome that is inflatable to assume a desired configuration.
A terrarium is a fully enclosed, small container, wholly or predominantly made of glass or other transparent material, the terrarium being adapted for the indoor cultivation of moisture-loving plants. The earliest form, known as a Wardian case, was invented by an English botanist in the 19th century, the case being constituted by a box-like glass dome fitted over a metal, earthenware or wooden base serving as a pot for growing living plants. Normally, moisture from an exposed plant is dissipated into the atmosphere through transpiration, so that the plant must be watered at frequent intervals, but in a terrarium the loss of moisture is slight and it is not necessary to replenish the water except occasionally.
Because of the growing popularity of terrariums, they are now mass-produced and commercially available in rigid, transparent plastic form. The terrarium consists of a plastic base having a pot formation for receiving plant soil and a plastic dome or shell which fits over the base. Plastic terrariums come in a range of sizes, and the larger ones are not only fairly expensive, but because of their size they are not easily stored when not in use, particularly in a small apartment dwelling.
But a more important drawback of existing types of rigid glass or plastic terrariums is that they are not hermetically sealed, so that even though these enclosed terrariums reduce the loss of moisture, they are incapable of maintaining an atmosphere of high humidity of the type necessary, for example, in promoting the growth of certain exotic or tropical plants. It is for this reason that when bell jars are used as terrariums, it is the present practice to apply grease or oil to the rim of the jar in order to improve the seal thereof.
With a view toward overcoming the drawbacks of existing types of rigid terrariums, there is disclosed in the above-identified copending patent application, a terrarium assembly which makes use of a flexible plastic dome mountable on a base to create a hermetically sealed enclosure, the dome being inflatable to assume a desired configuration.
In the collapsible terrarium assembly disclosed in this copending application, the dome is attached to the base by means of a coupling ring, the rim of the dome being permanently secured to the coupling ring which in turn is joinable to the base. Hence while it is possible to replace a given dome with another dome of different size or shape, the replacement dome requires its own ring, which makes it more costly. Moreover, in the prior arrangement, to ensure a hermetic seal, gaskets are necessary, which further adds to the cost and complexity of the assembly.